Evidence on the impact of endocrine-disrupting chemical exposure on human health has continued to grow, with recent research suggesting the chemicals confer an increased risk for developing diabetes, obesity, hormone-sensitive cancers and other diseases, according to an executive summary of a scientific statement issued by the Endocrine Society.
In a preview of the Endocrine Society’s second scientific statement regarding endocrine-disrupting chemicals (EDCs), researchers also noted that, like hormones, EDCs exhibit dose-response properties, and that the chemicals can act in even very low concentrations. Fetal development and early childhood, researchers wrote, are particularly vulnerable periods for exposure to chemicals such as bisphenol A (BPA), phthalates, pesticides and industrial chemicals, and exposure during developmental phases can “set the stage” for various diseases.
“We’re, in the last 5 years, having a much better understanding of the molecular mechanisms that underlie the actions of EDCs,” Andrea C. Gore, PhD, professor and Vacek chair of pharmacology at the University of Texas at Austin, said during a presentation outlining the executive summary. “Very importantly, the effects [of EDCs] that we observe really depends upon when and how we assess that effect. So not only are developmental exposure and timing of exposure important, but the timing at assessment is important as well. In humans, there are stronger epidemiological associations between EDCs and chronic diseases.”
Andrea C. Gore
The statement follows a 2009 report examining the state of scientific evidence on EDSs and their threat to human health. That report also detailed an increase in the number of chemicals — from 120,000 in 1988 to 250,000 in 2008 — many of which remain untested today, Gore said during her presentation.
EDCs mimic, block or otherwise interfere with the body’s natural hormones. The chemicals are found in many everyday household items, including plastic bottles and the linings of canned goods, but linking chemical exposure to endocrine diseases, which may take decades to manifest, has posed a challenge to researchers.
In the scientific statement, researchers reviewed seven endocrine systems and the effects EDCs have on each, including diabetes, obesity and cardiovascular health, which Gore cited as an emerging area of interest.
“This topic really was not reviewed thoroughly 5 years ago, and that’s because 5 years ago, there wasn’t strong literature on links between EDCs and these diseases,” Gore said. “This has really been an emerging field where there is much stronger evidence now.”
Several EDCs are now strongly associated with these diseases, Gore said, including BPA, phthalates, persistent organic pollutants and pesticides. In animals, exposures to these chemicals disrupted adipogenesis, energy balance and insulin synthesis, among other changes, while cross-sectional epidemiologic studies in humans also revealed strong links between EDC exposure and risk for diabetes, obesity and cardiovascular disease.
EDC exposure also affects female and male reproductive health and has been linked to fertility problems, polycystic ovary syndrome, an increased risk for prostate cancer, thyroid diseases, hormonal cancers and increased neurodevelopmental problems.
Gore said that clinicians should include the risks related to EDC exposure when discussing healthy habits with their patients.
“Clearly endocrinologists need to do a better job of talking to their patients about lifestyle,” Gore said. “I think when doctors talk about lifestyle to their patients, they typically emphasize a healthy diet and exercise. But I would be surprised if, as part of the healthy diet conversation, they talk about ... trying to remove processed foods, or staying away from microwaving the plastics. You may have a healthy meal, but if it’s in a [microwaved] plastic container, it’s leaching chemicals.”
The full scientific statement will be published in
later this month
– by Regina Schaffer
Disclosure: Gore and the other study authors report no relevant financial disclosures.